The long range goal of the work described in this proposal is to identify and characterize the mechanism by which extremely low frequency electromagnetic fields (EMFs) interact with living organisms. In pursuit of this goal we propose (1) to determine whether or not electric and magnetic fields play a similar role in inducing effects and (2) to examine the role of waveform of applied fields in producing effects. Both sinusoidal and pulsed electric and magnetic fields will be applied at levels such that induced currents will be in the neighborhood of 1 Mu A/cm squared and maximum magnetic field intensities will be less than 20 Gauss (2.0 millitesla). The effect of sinusoidal fields will be compared with pulsed fields and then the pulsed waveform will be decomposed into low and high frequency components and the effects of the individual components will be examined. The test organism to be used inthese studies is the slime mold Physarum polycephalum, which has been shown to be sensitive to both sinusoidal and pulsed EMFs. Bioeffects will be assayed using a novel countercurrent distribution technique which is a liquid-liquid chromatography method for cells. The technique is very sensitive to changes in cell surface charge and cell surface composition and is capable of providing a "fingerprint spectrum" of a cell population based on these properties. Preliminary experiments have established that the cell surface is modified by exposure to EMFs. The pulsed field waveform that will be employed is identical to one used clinically for healing ununited bone fractures by a device manufactured by Electro-Biology, Inc. (Fairfield, NJ). Pulsed fields have also been reported to have anut-tumor activity and to have the capability of modulating hormone-receptor interactions. Much of the interest in low frequency and sinusoidal field effects is related to concerns for hazards associated with high voltage power transmission lines. Knowledge of the mechanism(s) of EMF interaction would permit (1) improvement of the efficacy and safety of clinical devices currently in use, (2) development of new devices for clincial applications, (3) progress toward probing cellular processes with EMFs, and (4) establishment of design criteria for transmission lines in a manner that would invite public acceptance.